Railway signaling system



Feb 29, 1945- J. J. VAN HORN RAILWAY SIGNALING SYSTEM Filed Oct. 29, 1942 2 Sheets-Sheet 1 Feb. 20, 1945. 1 L VAN HORN RAILWAY SIGNALING SYSTEM Filed oct. 29, 1942 2 sheets-sheet 2 INVENTOR amefJ I/an [fom am@ H16 ATTORNEY wwmw ENS. l

Patented F eb. 20, 1945 UNITED STATES VPn'rErr-i OFFICE RAILWAY SIGNALING SYSTEM James J. Van Horn, Pittsburgh, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application October 29, 1942, Serial No; 463,733

8 Claims. (Cl. 246-130) My invention relates to railway signaling systems and particularly to improved means for controlling the crossing signals at an intersection of a highway with a stretch of single track railroad over which traffic may move ineither direction, and whichis equipped with signaling apparatus of the type shown in my copending application for Letters Patent of the United States, Serial No. 412,279, filed September 25, 1941, now Patent No. 2,344,333, dated March 14, 1944.

In my application identied above, there is shown a signaling system for a single trackl railroad over which traino may move in either direction. The system shown in thatV application operates without line wires except for the portions of a track stretch adjacent a highway intersec tion. In the system shown in that application each track section in the track stretch is equipped with two track circuits, one for each direction of tra'ic. steady energy to either end of the track stretch, while the track circuits are arranged so that when the track stretch is vacant, this steady energy is cascaded from one section to another throughout the track stretch to energize traic locking means at the other end of the track stretch and thus permit the direction of traic in the track stretch to be reversed. In addition, there are means at each end of the track stretch eiective after the stretch has been conditioned for either direction of traflic to supply coded energyto the section at the exit end of the track stretch, and the track circuit apparatus for each section is arranged so that this coded energy is cascaded from one section to another to the entrance end of the track stretch to control the signal at the entrance end of the stretch.

As shown inFig. 4 of my application identified above, where a highway crossing is encountered, track sections employing steady energy track circuits are provided on either sideI of the inter.- section to control the highway crossing signals, while a linecircuit is provided to carry around the approach sections at the highway crossing Means are provided to at times supply play stop indications until the line circuit is -repaired.

It is an object ofv` myl invention to provide for use in ay system of the type described improved means to control highway crossing signals.

A further obj'ectof my invention is. to provide improved means of the type described in which the coded and steady 'energy employed to control the signals inthe track stretch` istransmitted through the trackrails of the approach. sections at a highway intersection instead of over a line circuit extending around these sections;

Another object of my invention is4 to provide improved means` of they type described which are arranged so that the steady or codedl energy emh ployed in the control of. the signals and supplied to theV approach sections operates the track circuit apparatus for these sections to normally maintain the -crossing signals inactive, these means being` also arranged so that when conditions are'such that neither steady nor coded signal control, energy is supplied to an approach section, energy of a distinctive character isisupplied to such approach section and operates the track circuit apparatus for the section to discontinue operation of the crossing signa-ls when the section isvacated.

- A further object'of my invention is to provide a system of the. type described in which coded energy of a distinctive, code frequency is employed in the approach sections to dis-continue operation of the highway crossing signals Other objects of my invention and features of novelty will be apparent from the following description taken in connection with the accompanying drawings.

I shall describe one form of apparatus embodying myv invention, and shall then point out thenovel features thereof in claims.

In practicing my invention, I provide each approach section with track circuit apparatus similar to that provided for eachof the other track sections in the track stretch, and arrange the track circuits for the approach sections so that on the supply of steady energy or of coded energy of a train governing frequency to either end of an approach section a crossing signal control relay at the other end of the approach section is picked up, while energy of the same type as is supplied tor such approach section, is supplied to thesectionadjacentsuch other end of the approach section. The track circuits for the approachsections are also arranged so that when neither steadynor coded signal controlv energy is suppliedA to a section, coded energy of a distinctive codefrequency is supplied to the section rails, and, when the section is vacant, energizes means to prevent operation of the crossing signals, but will not cause energy of this code frequency to be supplied to the rails of the adjacent section.

Referring to Figs. 1A and 1B of the drawings, there is shown therein a stretch of single track railroad over which traic may move in either direction. The track stretch includes an intersection with a highway and this crossing is protected with suitable crossing signals XS, while the track stretch is provided with means ernbodying this invention for controlling the crossing signals.

This invention is directed to the apparatus for the approach sections at either side of the highwaycrossing and to the apparatus at the adjacent ends of the adjoining track sections. This invention is not concerned with the apparatus at other points in the track stretch or at the ends of the single track stretch except insofar as the equipment of this invention is intended to operate in conjunction with that apparatus, and the equipment at those locations may be constructed as shown in my application for Letters Patent of the United States, Serial No. 412,279.

In order to simplify the disclosure and facilitate understanding of my invention, only the equipment for the approach sections and for the adjacent ends of the adjoining'sections has been shown in the drawings.

The rails I and la of the track stretch are divided by means of the usual insulated rail joints 3 into a number of track sections. Each of these sections is identified by the reference character T with a distinguishing numerical prex which also identifies the apparatus associated with that section.

To facilitate description of the equipment it will be assumed that the right-hand end of the track stretch is east and that the left-hand end of the stretch is west, so that train movements from left to right are eastbound and train movements from right to left are westbound.

The track section 9T is a relatively short section which includes the highway intersection. This section has at one side the eastbound approach section 8T, and at the other side the westbound approach section IDT, while means governed by traffic conditions in these sections are provided .to control the relay XR. which governs the crossing signals XS.

The short intermediate section 9T is provided for the purpose of insuring that on movement of a train through the track stretch in either direction, operation of the crossing signals will be continued until the train clears the intersection. If this method of operation of the crossing signals is not required, the intermediate section 9T may be omitted and the approach sections 8T and IUT may adjoin.

In the system shown in the drawings the control relays WTM and ETM, and the directional stick relays WSR and ESR, cooperate with the track relay STR of the intermediate section 9T to control the relay im which governs the crossing signals XS. However, the invention is not limited to the use of this form of crossing signal controlrapparatus and an interlocking relay of well-known construction, or other appropriate apparatus, may be employed to control the crossing signals.

The section ST- is provided with a track circuit of the conventional type employing steady entrl ergy, while the steady and coded energy employed in the control of traffic in the track stretch is transmitted between the approach sections through local wiring.

Each of the approach sections is, in effect, provided with two track circuits, one eastbound and one westbound. These track circuits are similar in arrangement and operation to the track circuits employed -in the track sections of the system shown in my application identified above. Each track circuit for each section includes a code following track relay TR at one end of the section and a source oi energy, such as a( battery TB, at the other end of the section. In addition, each approach section has at each end thereof a steady energy detecting track relay TRA.

Each track section also has at each end thereof a coding relay CTM having contacts controlling connection of the associated track battery and track relays across the section rails.

Each of the code following track relays TR has associated therewith a front contact repeater relay FSA, and a back contact repeater relay BSA. The relays FSA and BSA are of a type the contacts of which are slow to release, while each of these relays may have a snubbing resistor connected across the terminals of its winding to increase the release period of the relay. The relays FSA and BSA are proportioned so their contacts will remain picked up throughout the longest code interval during which the supply of energy to the relay is interrupted.

The code following track relays 8WTR and IUETR at the ends of the approach sections 8T and IUT adjacent the highway intersection have associated therewith code detecting relays CDR which are energized through decoding transformers DT. The relays CDR and the transformers DT are proportioned so that the relays will not become picked up when the associated track relay is following coded energy of a low code frequency, such as 20 code frequency, which is employed for detection purposes, but will become picked up when the track relay is following coded energy of a higher code frequency, such as 75 or 180 code frequency, which is employed for traiiic governing purposes.

Each approach section has at the end thereof remote from the highway intersection a coding device 20CT having a contact which, when the device is energized, is opened and closed at a rate such as to supply 20 code impulses a minute which are separated by periods of equal duration in which no energy is supplied.

The relays and other equipment except the track relays are supplied from suitable sources of direct current, such as storage batteries, located at appropriate points in the track stretch. The terminals of these sources are designated B and C in the drawings.

The equipment is shown in the condition which it assumes when the track stretch is vacant and steady energy is supplied at the east end of the track stretch. As explained in my application identified above, steady energy is supplied at the east end of the track stretch and is cascaded from one track section to another to the west end of the stretch to energize traffic locking means to permit the stretch to be conditioned for passage of an eastbound train through the track stretch.

The track circuit apparatus provided by this invention for the approach sections is arranged so that on the supply of steady energy-to either end of the stretch, it will be cascaded through the approach sections to the portion of the track stretch at the other sidelof these sections, While the steady energy supplied through the approach sections causes the track circuit apparatus for the approach sections to operate to maintain the y and back contact 26 of relay IIEBSA to coding relay lWCTM. The contacts 21 and 28 of this relay, therefore, are steadily picked up to connect the track battery IUETB across the rails of section IGT and cause steady energy to be supplied to this section. In addition, as the contacts of relay illWCTM are steadily picked up, track relays IDWTR and IUWTRA are not connected to the section rails and remain released.

The steady energy supplied to the rails of section IllT feeds over back contacts 30 and 3| of coding relay WECTM to track relays IDETR and lSETRA and causes the contacts of these relays to be steadily picked up so contact 32 of relay iilETR establishes the circuit of relay IUEFSA but does not establish the circuit of relay IBEBSA. Accordingly, relay IDEBSA is released and its back contact 33 establishes the circuit of relay iiETRA, While its contact 34 interrupts the circuit of the primary Winding of the decoding includes front contact 55 of relay STR, front'contact 58 of relay WTM, and front contact 51 of relay ETM. The relay XR, therefore, is` energized and its contact 58 is picked up and interrupts the circuit of the crossing signals so these signals are inactive at this time.

If it is desired to condition the stretch to permit a Westbound train to pass through the stretch, means, not shown, at the right-hand or east "end of the stretch are operated to permit clearing of the Westbound signal governing entrance of trains into the stretch and to cut off the supply of steady energy to the west end of the stretch. When the supply of steady energy to the stretch is interrupted, the track relay for each section releases and cuts off the supply of steady energy to the adjoining section so the supply of steady energy is cut oil' from the varous sections in succession throughout the track stretch including the approach sections, While the contacts of the coding relays CTM are released and connect the associated tracks relays across the section rails.

When the 'supply of steady energy at the West end of the stretch is cut off, apparatus, not shown, at that location causes coded energy of suitable code frequency, such as 75 or 180 code frequency, to be supplied to the west end of the stretch. The means for causing coded energy to be-supplied to the West end of the stretch are not a part oi this invention, and are shown and described in l my application identified above.

transformer HJEDT to prevent consumption of energy by this transformer at this` time.

As relay iE'IRA is picked up, its contacts 35 and 35 establish a circuit to supply energy to the relay ETM, while its front contact 31 establishes a circuit including front contact 38 of track relay STR for supplying steady energy to coding relay BWCTM.

As steady energy is supplied to relay SWCTM, its contacts 4i] and 4| are picked up and interrupt connection from the track rails to track relays SWTR and SWTRA, While these contacts conneet the track battery 8ETB across the section rails and steady energy is supplied over back contacts 43 and 1M of coding relay SECTM to track relays SETR and BETRA.

As track relay SETR is steadily picked up, its front contact i5 establishes the circuit to supply energy to relay BEFSA, but does not establish the circuit to supply energy to relay 8EBSA, and contact i6 of relay SEBSA is released and establishes the circuit of relay SETRA. As relay tETRA is energized, its contacts 41 and 43 establish a circuit to supply energy to relay WTM, While as relays BETR and BEFSA are yboth energized, steady energy is supplied over front contact 52 of relay BETR and front contact 53 of relay SEFSA to coding relay 1WCTM so that its contacts and 5| are picked up and connect the track battery 1ETB across the rails of section iT. This causes steady energy to be supplied to section 1T from which the supply of steady energy is repeated throughout the other track sections to the West end of the single track stretch.

As relays ETM and WTM are picked up, and as track relay STR isalso picked up, energy is supplied to the relay XR over the 'circuit which On the supply of coded energy to the west end of the track stretch, coded energy is cascaded through the successive track sections to section 1T so that coded energy is supplied over back con= tacts vand 5| of coding relay 1WCTM to track relay 1WT'R. Accordingly, this-relay follows code and energy as supplied over the front point of its contact 55`to relay 1WFSA, and is supplied over the back point of its contact 55 and front contact 55 of relay 1WFSA to relay 1WBSA.

On picking up of relay 1WFSA, its conta-ct 51 interrupts the circuit for supplying energy of 20 code frequency to coding relay SECTM, (the manner in which 20 code is supplied will be explained in detail hereinafter), while on picking up of relay 'IWBSA its front contact 58 establishes a circuit including front contact 6U of relay 1WTR for supplying energy to relay SECTM so that the energy supplied to the coding relay BECTM is coded at the same frequency as the energy supplied to section 1T, and the relay SECTM causes coded energy of this frequency to be supplied to the west end of section 8T.

In addition, on picking up of relays 1WFSA and iWBSA their contacts 6| and 62 interrupt the circuit of the code transmitter ZBCT at this location and it ceases to operate.

The-coded energy supplied to the Westend of section 8T feeds over back contacts lll and'l of coding relay `SWCTM to relay BWTR. When relay SWTR follows code, energy is supplied over the front point of its contact 64 to relay BWFSA' and is supplied over the back point of its contact t4 and front contact B5 of relay WFSA to relay SWBSA. On picking up of relay BWBSA, its back contact. 66 interrupts the circuit of relay 8WTRA and its front contact |36 connects the resistance 81 in multiple with track relay BWTR. The resistance 61 is of substantially the same Value as the winding of relay 8W'IRA so the track circuit characteristics are substantially` the same whether or. not track relay BWTRA is included in the track circuit.

establishes the circuit including contact 19 of relay BWTR for supplying energy to the primary winding of decoding transformer BVVDT so that on continued code following operation of relay SWTR energy effective to pick up the contact of relay SWCDR is supplied through the decoding transformer to relay IlWCDR, while this energy is rectified by contact 'II of relay 8WTR in the manner explained in Letters Patent of the United States No. 2,237,788, granted to Frank H. Nich- Olson and Leslie R. Allison on April 8, 1941.

On the supply of energy to relay BWCDR, its contact 'I5 is picked up and establishes a circuit to supply coded energy to relay IGECTM. This circuit is traced from terminal B through front contact I6 of relay 8WTR, front contact 15 of relay SWCDR, back contact 18 of relay SWIRA, wire '19, front contact 80 of relay STR, and winding of relay IDECTM to terminal C. As the circuit for supplying energy to relay IOECTM includes a contact of the code following track relay 3V/TR, the energy supplied to relay IDECTM is coded at the same rate as the energy supplied to section 9T, and relay IOECIM causes coded energy of this code frequency to be supplied to the west end of section IDT.

The coded energy supplied to the west end of section IGT feeds over back contacts 2 and 28 of relay IUWCTM to relay IGWTR and causes code following operation of this relay. On picking up of contact 33 of relay IUWTR energy is supplied to relay IQWFSA, while on release of contact 83 of relay IDWTR energy is supplied to relay IUWBSA over the circuit which includes front contact 84 of relay IDWFSA.

On picking up of relay IIJWBSA its contacts 86 and 8l establish a circuit to supply energy to crossing signal control relay ETM. On picking up of relay IIlWFSA its contact 88 interrupts the circuit for supplying energy of 2f) code frequency to relay IBWCTM, while its contact 89 interrupts the circuit for supplying energy to the code transmitter QCT at this location. In addition, on picking up of relay ISIWFSA its contact 99 establishes a circuit including front contact Ill of code following track relay IllWTR for supplying energy to coding relay IIECTM and this relay operates to supply coded energy to the west end of section IIT, while the track circuit apparatus, not shown, for section IIT causes this coded energy to be repeated into the adjacent section. Similarly, coded energy is supplied through the other sections until the east end of the stretch is reached, and the coded energy supplied to this point will cause the headblock signal at that point to display a proceed indication and thus permit a westbound train to enter the track stretch.

It will be seen, therefore, that on the supply of coded energy to the west end of the track stretch, this coded energy is cascaded through the approach sections associated with the highway crossing, and that the track circuit apparatus for these sections operates to maintain circuits for the crossing signal control relays WTM and ETM'so that they maintain a circuit for relay XR to cause it to keep the crossing signals inactive.

The relays WTM and ETM are of a type the contacts of which are slow to release so that the contacts of these relaysl remain picked up during periods in which the supply of energy thereto is momentarily interrupted, as may occur on a change from the supply of steady energy at one end of the track stretch to the supply of coded energy at the other end of the track stretch.

Operation of equipment on movement of a westbound train through the track stretch When a westbound train enters the track stretch, it shunts the rails of each section it enters, and thus cuts off the supply of coded energy to the sections in the rear. Accordingly, as soon as a westbound train enters the track stretch, the supply of coded energy to the equipment at the east end of the stretch is cut oi and the signal governing entrance of westbound trains into the stretch is caused to display its stop indication.

In addition, when the supply of coded energy to the east end of the track stretch is cut off, the equipment at that location operates as described in my application referred to above to cause steady energy to be supplied to the east end of the track stretch, unless the remote control apparatus has been operated to cause the signal at the east end of the track stretch to be re-cleared on the subsequent supply of coded energy to the equipment controlling that signal.

When the westbound train enters section IDT, it shunts the track relay IDWTR so that its contact 83 thereafter remains released and does not establish the circuit to supply energy to relay IDWFSA which releases so its contact 84 interrupts the circuit of relay IUWBSA to release that relay and cause its contacts 86 and 8T to interrupt the supply of energy to relay ETM. Relay ETM, therefore, also releases and its contact 51 interrupts the circuit of relay XR so that back contact 58 of relay XR closes and establishes the circuit of the crossing signals to cause them to operate and warn users oi the highway of the approach of a train.

In addition, on release of relay ETM its contact 9d establishes a pick-up circuit for westbound stick relay WSR. This circuit is traced from terminal B through front contact 95 of relay WTM, back contact 94 of relay ETM, back contact 9S of relay ESR, and winding of relay WSR to terminal C. At this time, therefore, the relay WSR will pick up, and, as hereinafter explained, will establish a circuit for relay XR to discontinue operation of the crossing signals after the train vacates sections IOT and 9T.

When relay IUWFSA released, its contact interrupted the circuit of relay IIECTM, while its contact 89 established thecircuit including back contact 98 of relay IIEFSA and back contact 98 of relay IIEBSA for supplying energy to code transmitter 2UCT so this device starts to operate.

In addition, when relay IUWFSA released, its contact 38 established the circuit including a contact of code transmitter 20C'I as well as back contact 25 of relay IIEFSA and back contact 26 of relay IIEBSA for supplying energy of 20 code frequency to relay IUWCTM. This relay, therefore, operates to cause energy of 20 code frequency to be supplied to the east end of section IGT, but as long as this section is occupied, this energy does not reach track relay IDETR.

When the westbound train enters section 9T, track relay STR releases and its contact 55 additionally interrupts the circuit of relay XR, and establishes a stick circuit including front contact |00 of relay WSR to keep relay WSR energized after release of relay W'IM. In `addition, on release of relay STR, its contact 38 interrupts the circuit of coding. relay BWCTM,

while its contact 80 interrupts the circuit of coding relay IGECTM so that these coding relays are certain to remain released and connect the associated track relays across the section rails.

When the train enters section 8T, it shunts relay BWTR and relays SWFSA, BWBSA and SWCDR release. On release of relay BWBSA its contacts 13 and 'Ill interrupt the supply of energy to the relay WTM and this relay releases and its contact t additionally interrupts .the circuit of relay XR. t

When the train enters section 1T, track relay 'EWI'R is shunted and energy is no longer supplied to relays TWFSA and 'IWBSA and these relays release to establish the circuit to supply energy to the associated code transmitter ZUCT and to supply energy of code frequency to the relay SECTM so that it operates to supply energy of 20 code frequency to the west end of section 8T. The circuit for supplying energy to the code transmitter includes back contact 62 of relay 1WBSA, back contact 5I of relay 1WFSA, and back contact Il of relay SEFSA, while the circuit for supplying energy to coding relay SECTM includes a contact of the code transmitter ZUCT, back contact IIE of relay SEFSA, back contact 5l of relay lWFSA, and back contact; 58 of relay lWBSA.

For purposes of illustration it will be assumed that the remote control apparatus governing the signal at the east end of the'stretch and controlling entrance of westbound trains into the track stretch has been operated -to re-clear this signal so that the equipment associated with that signal does not operate to supply steady energy to the east end of the track stretch. Accordingly, as the train vacates each section, both of the track circuits for that section remain deenergized, and when the train vacates section IIT, relays IIEFSA and I IEBSA remain released and maintain the circuits for supplying energy to the code transmitter 20CT, and for supplying energy of 20 code frequency to the coding relay IUWCTM.

When the train vacates section IDT, the energy of 2O code frequency supplied to the east end of this section feeds over back contacts and 3^I of relay IOECTM to relay IDETR so that contact 32 of relay IUETR causes energy to be supplied to relays IDEFSA and IllEBSA. On picking up of relay IElEBSA its contacts m2 and |03 estab lish a circuit to supply energy to relay ETM and Y" the contacts of this relay pick up so that `contact 5l permits energy to be supplied to relay XR after section 9T is vacated, while front contact 94 of relay ETM establishes a stick circuit for relay WSR. This circuit includes front contact 94 of relay E'IM, back contact 95 of relay WTM, and front point of contact HB5 of relay WSR, .and keeps relay WSR picked up after the train vacates section 9T and relay STR picks up.

On picking up of relay IBEBSA, its Contact '34 establishes the circuit of the primary Winding of decoding transformer IEDT,'and energy is supplied through this transformer' to relay IEBECDR. However, as pointed out above, the transformer IIJEDT and the relay IQECDR are so designed and proportioned that the relay IIlECDR will not pick up when the relay IDETR is following energy of 2O code frequency. Accordingly, contact IUS of relay IIJECDR remains released and interrupts the circuit of relay SWC'IM .and the coding relay A8WCTM remains released and connects the relay BWTR across the rails of section 8T.

In addition, o n picking up ofrelay IUEBSA its contact 33 interrupts the circuit of relay IDE'IZRA and connects a resistor |01 in multiple with relay vIIIE'I'R.

When the train vacates section 9T, track relay STR. Epicks up and interrupts one stick circuit for relay WSR, but this relay is held picked up `by energy supplied over the stick circuit which includes front contact 94 of relay ETM, back contact95 of relay WTM, and front contact |05 of relay WSR;

On picking up of relay STR, energy is supplied to relay XR over the circuit which is traced from terminal B through front contact of re1ay`9TR, frontcontact I08 of relayWSR, front Contact 5l of relay ETM, and winding of relay XR to .terminal C. The relay XR, therefore,` picks up and its contact 58 cuts ou the supply of energy tothe crossing signals XS and operation of these .signalsis discontinued.

When the train advances far enough to vacate section 8T, the energy of 20 code frequency supplied at the West end of this section feeds to the track relay BWTR and produces code following operation of this relay With the result that energy is supplied to relays BWFSA and SWBSA. On vpicking up of relay BWBSA, its contact 66 interrupts the circuit of relay 8WTRA, while its contact 69 establishes the circuit of the primary winding of transformer 8WDT and energy. is supplied through this transformerr to relay BWCDR, .but as relay SWTR is following energy of 20 code frequency, the relay BWCDR remains. released. As relay BWCDR remains released, its contact 15 interrupts .the circuit of coding relay IDECTM and that relay is-certain to remain released .and connect relay IDETR across the rails of resection IUT.

When relay SWBSA picks up, its .contacts 'I3 and I4 establish .a-circuit to supply energy to relay WTM and Vcontact 56 of this relay is picked up and establishes the originally vtraced circuit for supplying energy to relay XR, while contact of relay WTM interrupts the stick circuit for relay WSRgso relay WSR releases with the result that its contact |05 Aadditionally interrupts the stick circuit for -the relay, while its contact IDS interrupts the circuit over which energy was supplied to relay XR prior to picking up of relay WTM,

When the train advances far enough to vacate the track stretch, rcoded energy may again be supplied to the West end-of the track stretch and will be cascaded through the successive Vtrack sections -to section v'IT where it will cause code following operation of the track relay 'IW'IR with the result that energy is supplied to relays TWFSA and .'IWBSA.

On pickingup'of relay IWFSA its back contact 51 interrupts the circuit for supplying energy of 20 code frequency to coding relay 8EC'I'M, while on 4picking up lof relay TWBSA `its front contact 5B establishes the circuit including front contact F!! of relay 'IWTR for supplying energy to the relay fECTM. Accordingly, the relay `SECTM now operates to supply-to section 8T coded energy ofthe same code frequency as that supplied to the west end of the track stretch. The code frequency of this energy is much .higher than th at of the energy of 20 code frequency previouslysupplied tosection 8T. On the lsupply of this energy of higher :code frequency to track relay SWTR, relays BWFSA and 8WBSA are maintained energized, while suil'icient energy is now supplied through the decoding transformer SWDT to relay BWCDR to pickup that relay so that contact of relay BWCDR establishes the circuit including front contact 16 of relay 8WTR, back contact 18 of relay BWTRA, and front contact 80 of relay STR for supplying energy to relay IUEC'I'M. Accordingly, relay IOECTM now operates at the same rate as relay SWTR and causes energy of the same code frequency to be supplied to the West end of section IDT as is supplied to the west end of section 8T.

At this time, as previously explained, the relay I UWCTM at the east end of section IDT is being operated at a rate such as to cause energy of 20 code frequency to be supplied to the east end of section IUT.

On the supply of energy of 75 or 180 code frequency to the west end of section IIIT, this energy feeds to track relay IDWTR. during the periods in which the contacts of relay IUWCTM are released. Because of the substantial difference in the code frequency of the energy supplied to the two ends of the section there are frequently recurring intervals when the contacts. of relay IUECTM are picked up and the contacts of relay IDWCTM are released. Furthermore, the released periods of the relay IOWCTM are relatively long so that more than one impulse of coded energy may be supplied to the relay IUWTR during one released period of the contacts of relay IDWCTM.

On the supply of coded energy to relay IOWTR, its contacts pick up and establish a circuit to supply energy to relay IDWFSA so that the contacts of relay IIJWFSA pick up with the result that its contact 88 cuts off the supply of energy of 20 code frequency to coding relay IDWCTM so that the contacts of this relay thereafter remain re leased and maintain the circuit of relay IIIWTR.

As the contacts of relay IIIWCTM remain released, energy is no longer supplied to the east end of section IUT and relay IUETR. remains released so that relays IBEFSA and IGEBSA' release. On release of relay IDEBSA its contacts |02 and |03 interrupt the supply of energy to relay E'I'M, but this relay is of a type which is slow in releasing so it remains picked up until after contacts 86 and 81 of relay IDWBSA pick up and established a circuit to supply energy to relay ETM.

In addition, on picking up of relay IUWFSA its contact 89 interrupts the circuit for supplying energy to the code transmitter ZGCT, While its con` tact 90 establishes the circuit including front contact 9| of relay IIIWTR for supplying energy to coding relay IIECTM so that it operates to supply to section IIT energy of the same code frequency as is supplied to section IUT,

On release of relay I DWTR subsequent to picking up of relay IIJWFSA, energy is supplied to relay IIlWBSA and it picks up so that its contacts 86 and 81 establish a circuit to supply energy to relay ETM and thus maintain the crossing sigcontrol apparatus has not been conditioned to re-clear the headblock signal governing entrance of Westbound trains into the track stretch, the equipment associated with that headblock signal will operate, as described in my application identied above, to supply steady energy to the east end of the stretch after entrance of the train into the stretch.

In the event that steady energy is supplied to the east end of the stretch, as the train vacates each section energy will be cascaded through the successive sections to section I IT, and when section I 5T is vacated, this steady energy will be supplied over back contacts 20 and 2I of relay I IECTM to relay I IETR so that its front contact 23 establishes the circuit to supply energy to relay IIEFsA.

On picking up ol relay I IEFSA, its contact 25 cuts off the supply of energy of 2G code frequency to relay IOWCTM and establishes the circuit including back contact 26 of relay I IEBSA for supplying steady energy to relay IDWCTM. Accordingly, the contacts of relay IBWCIM are held picked up and cause steady energy to be supplied to the east end of section IUT and prevent the supply of energy to relay IIIWTR so that it remains released.

As relay IIIWTR remains released, relay IDWFSA also remains released and the circuit of relay IIECTM is interrupted so that it remains released and maintains the circuit of relay I IETR With the result that relay I IETR remains picked up and maintains the circuit of relay I IEFSA so that it maintains the supply of steady energy to coding relay IiIWCTM.

When the train vacates section IOT, steady energy supplied at the east end of section IUT feeds over back contacts 30 and 3I of relay IDECTM to track relays IJETR and IUETRA and picks up the contacts of these relays. When relay IDETRA picks up, its contact 31 establishes a circuit to supply steady energy to coding relay BWCTM and the contacts of relay SWCTM pick up to cause steady energy to be supplied to the east end of section 8T and to prevent the supply of energy to track relay 8WTR. Accordingly, relays BWTR and SWCDR remain released and energy is not supplied to relay IOECTM so it remains released and maintains the circuits of relays IBETR and IOETRA energized with the result that contact 31 of relay IDETRA is maintained picked up and maintains the circuit for supplying steady energy to relay SWC'IM` In addition, on picking up of relay IDETRA its contacts and 36 establish o, circuit to supply energy to the relay ETM so relay ETM picks up, and, as explained above, establishes va circuit to supply energy to relay XR when section 9T is vacated to thereby discontinue operation of the crossing signals.

As relay BWTR remains released, the relays IlWFSA, 8WBSA and BWCDR are released so that contacts 13 and 14 of relay SWBSA interrupt the supply of energy to relay WTM.

As coding relay 8WCTM is supplied with steady energy. its contacts 40 and 4I connect the track battery 8ETB across the section rails and when the train vacates section 8T, energy feeds over back contacts 43 and 44 of relay SECTM to relays BETR and BETRA so that the contacts of these relays pick up. On picking up of relay 8ETRA, its contacts 41 and 48 establish a circuit to supply energy to relay WTM, with the result that relay WI'M interrupts the stick circuit for relay WSR and 'establishes acircuit-to `supply' energyfto rre'lay XR as'explained above.

-On picking -up of relay y"BETH, its contact 45 establishes 'a circuit to supply energy to relay SEFSA so that it picks vup and energt7 is supplied over front contact -52 of relay SETR and front Contact 53 of relay SEFSA to coding relay lWCTM.

Accordingly, relay 'IWCTM picks up and its contacts l? and 5! connect the battery IETB across the, section rails and prevent the supply of energy to relay VWTR so relays 'lWTR and TWFSA remain released and do not establish the circuit for supplying energy to relay SECTM. The relay fSECTM, therefore, remains released and maintains the `circuit of relays BETR and SETRA and Vthese relays maintain the supply of energy to relay l'IWCTM.

The steady energy supplied to section 1T will cause steady energy to be cascaded throughout the remainder of the track sections to the west end of the stretch where `the steady energy may be employed to release suitable traffic locking means.

The operation of the equipment'when steady energy is 'supplied at the east end of the stretch y and during movement of a westbound train through the track stretch has been explained. The operation of the equipment when steady energy is supplied at the West end of the track stretch, and during movement of an eastbound train through the track stretch, is similar to vthat described and in order to simplify the disclosure will not be traced in detail.

From the foregoing it will be seen that the track circuit `apparatus provided by this invention for the approach sections on either side of a highway crossing operates to cascade either steady energy or coded traic governing energy through 'the track stretch when energy of these types ris supplied to either end of the `track stretch, and that when the track vcircuit apparatus of the approach sections vis responding to energy oi either of these types, it operates tomaintain the crossing signals inactive.

In addition, it will be seen that when conditions are such that neither steady energy nor coded -traic governing energy issupplied to an approach section, energy of a distinctive code frequency is supplied to the section rails to detect when the section is vacated and to discontinue operation of the crossing signals, but that this type of coded energy will not be repeated into an adjoining section.

Furthermore, it `will be seen that the approach section track circuit apparatus provided by this invention is arranged so that on the supply of steady energy or of coded energy of traido governing frequency to an approach section at a time when energy of code frequency is being supplied thereto,'the supply of energy of 20 code irequency over the section rails is cut off and the track circuit apparatus for the section thereafter operates in the usual manner to supply steady energy or coded traliiic governing energy to an adjoining section.

Although `I have made reference to my colpending application identied hereinbefore and showing a remotely controlled single track system with which my present invention may advantageously be used, it will be understood that my invention is not limited to such use, and an understanding of that system, although helpful, is not essential for an understanding of the Vpresent invention `since an `appreciation that either steady energy ucr traflic governing Jcode will be supplied at the left-hand rendofisection 'IT or the right-hand `end of lsection HT, 4depending upon .the traic direction, is all that is required when taken with the detailed description :presented .herein r,for a clear understanding of the operation. The particular apparatus for supplying the steady .energy andthe traffic governing code to sections v'IT and HT forms no part of my present invention and accordingly has :not been illustrated in order to simplify the disclosure.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood -that various changes and modications may ybe made therein within the scope of the'appended claims Without departing from the spirit and scope of my invention.

Having thus described' my invention, what I claimis:

l. In crossing signal control apparatus for a stretch of railway track over which traiic may move in eitherdirection and'including an intersection with a highway, the rails of said stretch being divided by insulated joints into a plurality of track sections including a rst .approach section at one side of the intersection and asecond approach section at the other side of the intersection, the ltrack stretch being equipped with traffic governing signaling apparatus of a type in which steady or coded energy of a, trailic governing frequency is supplied `at one end of the track stretch at given times and is supplied at the other end of the track stretch at other times, each of the track sections in said track stretch being equipped with track circuit apparatus effective when energy is supplied to a vacant section at either end thereof and'such energy is supplied steadily or is coded at a 4trallc governing frequency tocause energy of the Vsame type to be supplied-to the corresponding end of the track section adjacent the opposite end of said vacant section, each of said approach sectionsA being equipped with means eective when neither steady energy nor coded energy of a trahie governing frequency is supplied tosuch section to cause energy-of a distinctive code frequency to be supplied to the rails of such section, a crossing signal for said intersection, and means responsive to the supply of steady energy or'of coded energy of said traic governing frequency or of said distinctive code frequency over the rails of said approach sections for controlling said crossing'signal.

2. In crossing signal control apparatus Ifor controlling the signal at the intersection between a highway and a stretch of railroad track over which traic vmay move inA either direction, the rails of said track stretch `being divided by insulated joints into a plurality of track sections .including a rst approachsection at-one side of the intersection and a second approach section at the other side of the intersection, said track stretch being equipped with traflic governing apparatus i of a type in Which'steadyenergy or coded energy of 'a trailc governing frequency `is supplied to one end of the track vstretch yat given times and is supplied to the other end of the naar stretch' section adjacent the opposite end of said vacant section, in combination, means for each of said approach sections effective when neither steady energy nor coded energy of a traffic governing frequency is being supplied over the rails of such section to supply to the rails of such section coded energy of a distinctive code frequency, and means responsive to the supply of steady energy or of coded energy of either said traflc governing frequency or of said distinctive code frequency over the rails of said approach sections for conti'olling said crossing signals.

3, In crossing signal control apparatus for controlling the signal at the intersection between a highway and a stretch of railroad track over which traiic may move in either direction, the rails of said track stretch being divided by insulated joints into a plurality of track sections including a first approach section at one side of the intersection and a second approach section at the other side of the intersection, the track stretch being equipped with a traflic governing signaling system of a type in which steady energy or coded energy of a trail'ic governing frequency is at times supplied to the end of the track stretch at said one side of the intersection and is cascaded through the intervening track sections to the end oi' the rst approach section remote from the intersection provided the intervening track stretch is vacant and at other times is supplied to the end of the track stretch at said other side of the intersection and is cascaded through the intervening track sections to the end of the second approach section remote from the intersection provided the intervening track stretch is vacant. each approach section being equipped with track circuit apparatus effective on the supply of steady energy or of coded traflic governing energy to the end of said section remote from the intersection provided the section is Vacant to cause energy of the same type to be supplied to the adjacent end of the other approach section, each approach section also being equipped with track circuit apparatus effective on the supply of steady energy or oi coded traffic governing energy to the end of said section adjacent the intersection provided the section is vacant to cause energy of the same type to be supplied to the adjacent track section at the end of the approach section remote from the intersection, in combination, a crossing signal for said intersection, means for each approach section effective in the absence of the supply of steady energy or of coded trafhc governing energy over the rails of such section to supply coded energy of a distinctive character to the rails of such section, and means responsive to the supply of steady energy, of coded traic governing energy, or of coded energy of said distinctive character over the rails of said approach sections for controlling said crossing signal.

4.-. In crossing signal control apparatus for controlling the signal at the intersection between a highway and a stretch of railroad track over which traffic may move in either direction, the rails of said track stretch being divided by insulated joints into a plurality of track sections including a first approach section at one side of the intersection and a second approach section at the other side of the intersection, the track stretch being equipped with traffic governing signaling apparatus which operates in such manner that steady energy or coded energy of a first type is at times supplied to the rails of the rst approach section at the end of said section remote from the intersection and at other times is supplied to the rails of the second approach section at the end of said section remote from the intersection, in combination, a crossing signal for said intersection, electroresponsive means for each approach section located at the end of the section adjacent the intersection and governed by energy supplied over the rails of such section, such means for each approach section being effective according as steady energy or coded energy of said first type is supplied thereto to cause steady energy or coded energy of said rst type to be supplied to the rails of the other approach section at the end thereof adjacent the intersection, other electroresponsive means for each approach section located at the end of the section remote from the intersection and governed by energy supplied over the rails of such section, such other electroresponsive means for each approach section being effective according as steady energy or coded energy of said rst type is supplied thereto to supply steady energy or coded energy of said first type to the adjacent end of the adjoining track section, means for each approach section effective when neither steady energy nor coded energy of. said first type is supplied over the rails of such section to supply to the rails of such sectionl coded energy of a second type, and means responsive to the supply oi steady energy, or of coded energy of either said rst or said second type over the rails of said approach sections for controlling said crossing signal.

5. In crossing signal control apparatus for controlling the signal at the intersection between a highway and a stretch of railroad track over which traffic may move in either direction, the rails of said track stretch being divided by insulated joints into a plurality of track sections including a first approach section at one side of the intersection and a second approach section at the other side of the intersection, the track stretch being equipped with traffic governing signaling apparatus which operates in such manner that steady energy or coded trailic governing energy is at times supplied to the rails of the first approach section at the end of said section remote from the intersection and at other times is supplied to the rails of the second approach section at the end of said section remote from the intersection, in combination, electroresponsive means for each approach section located at the end of the section adjacent the intersection and governed by energy supplied over the rails of such section, such means for each approach section being effective according as steady energy or coded traflc governing energy is supplied thereto to cause steady energy or coded tranic governing energy to be supplied to the rails of the other approach section at the end thereof adjacent the intersection, other electroresponsive means for each approach section located at the end of the section remote from the intersection and governed by energy supplied over the rails of such section, such other electroresponsive means for each approach section being effective according as steady energy or coded traffic governing energy is supplied thereto to cause steady energy or coded traffic governing energy to be supplied to the adjacent end of the adjoining track section, means for each approach section effective when neither steady energy nor coded traflic governing energy is supplied over the rails of such section to supply to the rails of such section energy of a distinctive type, and means responsive to the supply of steady energy, of coded traffic governing energy, or of energy of said distinctive type over the rails of said approach sections for controlling said crossing signal.

6. In crossing signal control means for use on a stretch of railway track over which traine may move in either direction, the rails of said stretch being divided by insulated joints into a plurality of successive track sections including a first, a second, a third and a fourth section, the track stretch being intersected by a highway at a point in the stretch in the vicinity of the adjacent ends of the second and third track sections, the track stretch being equipped with a traiiic governing signaling system of a type in which steady energy or coded traic governing energy is at times supplied to the rst section at the end thereof remote from the intersection and at other times is supplied to the fourth section at the end thereof remote from the intersection, in combination, a coding device, a source of current, and electroresponsive means at each end of each of said second and thirdsections and at the ends of the rst and fourth sections adjacent the intersection, each of said coding devices having contacts biased to a position in which they connect the associated electroresponsive device across the,

section rails and being movable on energization of the device to a position in which they connect the associated source of current across the section rails, means effective according as steady energy or coded traiiic governing energy is supplied over the rails of the iirst section to the electroresponsive means at the end thereof adjacent the second section to energize the coding device at the end of the second section remote from the intersection to cause steady energy or coded traffic governing energy to be supplied to the rails of said second section, means effective according as steady energy or coded energy is supplied over the rails of the fourth section to the electroresponsive means at the end thereof adjacent the third section to energize the coding means-at the end of the third section remote from the intersection to cause steady energy or coded traine governing energy to be supplied to the rails of said third section, the electroresponsive means at the adjacent ends of the second and third sections each being eifective according as steady energy or coded traffic governing energy is supplied thereto over the section rails to energize the coding device at the adjacent end of the other section to cause steady energy or coded traiiic governing energy to be supplied to the rails of such section., the second and third sections each having associated therewith means effective when neither steady energy nor coded traffic governing energy is supplied over the rails of such section to cause energy of a distinctive character to be supplied to the rails of such section, a crossing signal for said intersection, and means responsive to the supply of steady energy, coded traffic governing energy, or energy of said distinctive character over the rails of said second and third sections for controlling said crossing signal.

'7. In crossing signal control means for use on a stretch of railway track over which traiic may move in either direction, the rails of said stretch being divided by insulated joints into a plurality of successive track sections including a iirst, a second, a third and a fourth section, the track stretch being intersected by a highway at a point in the stretch in the vicinity of the adjacent ends of the second and third track secti'ons, the track stretch being equipped with a trafc governing signaling system of a type in which steady energy or coded traic vgoverning energy isl at times supplied to the rst section at the end thereof remote from the intersection and at other times is supplied to the fourth section at the end thereof remote from the intersection, in combination, a coding device, a source of current, and electroresponsive means ateach end of each of said second and third sections and at the ends of the first and fourth sections adjacent the intersection, each of said coding devices having contacts biased to a position in which they connect the associated electroresponsive device across the section rails and being movable on energization of the device to a position in which they connect the associated source of current across the section rails, the second and third sections each having at one end thereof means effective when the electroresponsive means at thatJ end of the section and at the adjacent end of the adjacent section is not supplied with steady energy or coded energy to cause coded energy of a distinctive character to be supplied to the rails of such section, the electroresponsive means at each end of the second and third sections and at the ends of the first and fourth sections adjacent the intersection controlling energization of the coding devices at the adjacent ends of the adjacent sections to cause steady energy or coded tralic governing energy to be supplied to the rails of such sections according as .steady energy or coded traflic governing energy is supplied to each of said electroresponsive means over the rails of the associated section, a crossing signal for said intersection, and means responsive to the supply of steady energy, coded traic governing energy, or coded energy of said distinctive character over the rails of said second and third sections for controlling said crossing signal.

8. In crossing signal control means for use on a stretch of railway track over which traffic may move in either direction, the rails of said stretch being divided by insulated joints into a plurality of successive track sections including a rst, a second, a third and a fourth section, the track stretch being intersected by a highway at a point in the stretch in the vicinity of the adjacent ends of the second and third track sections, the track stretch being equipped with a traffic governing signaling system of a type in which steady energy or coded traffic governing energy is at times supplied to the rst section at the end thereof remote from the intersection and at other times is supplied to the fourth section at the end thereof remote from the intersection, in combination, a coding device, a source of current, andfelectroresponsive means at each end of each of said second and third sections and at the ends of the first and fourth sections adjacent the intersection, each of said coding devices having contacts biased to a position in which they connect the associated electroresponsive device across the section rails and being movable on energization ofl the device to a positionin which they connect the associated'source of current across the section rails, the second and third sections each having at the end thereof remote from the intersection means eective when the electroresponsive means at that end of the section and at the adjacent end of the adjacent section is deenergized to supply to the coding device at that end of the section energy effective to cause coded energy of a distinctive character to be supplied to the rails of such section, the electroresponsive means at each end of the second and third sec-y tions and at the ends of the rst and fourth sections adjacent the intersection controlling energization of the coding devices at the adjacent ends of the adjacent sections to cause steady energy or coded traffic governing energy to be supplied to the rails of such sections according as steady energy or coded traffic governing energy is supplied to each of said electroresponsive means over the rails of the associated section, a crossing signal for said intersection, and means responsive to thev supply of steady energy, coded traffic governing energy, or coded energy of said distinctive character over the rails of said second and third sections for controlling said crossing signal.

JAMES J. VAN HORN. 

